package com.bjmashibing.system.OSFileIO;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

public class Test {


    public static void main(String[] args) {


    }


    private static void demo1(){
        //防并发
        Set<Object> demoSet = Collections.unmodifiableSet(new HashSet<>());

    }




}
